Unable to adjust PWM range to switch Auto mode

Use Case:ArduRover V4.5.6 with differential steering, Mission Planner 1.3.82

Transmitter: Flysky FS-16X Receiver: FS-16X

Pixhawk 6c with M10 GPS and PPM Encoder flashed from MP with rover firmware

Issue: I want to use a 2-pos Aux switch on FS-16X to switch modes between Manual (PWM range 910-1230) and Auto (PWM range 1231-1360).

I have tried all manner of endpoint and subtrim adjustments but have not successfully managed to get the switch adjusted to the Auto PWM range. Closest I get is down to 1380 PWM, too high for Auto mode.

Thanks for any responses … SOL in STL!

This is PX4, consult in